c. Primary progressive MS (PPMS) patients with all the following features: i. an increase of ≥1 EDSS point (if at randomization EDSS ≤ 5.0) or 0.5 EDSS point (if at randomization EDSS ≥5.5), in the last twelve months ii. ≥ 1 GEL at MRI performed within the last 12 months iii. positive cerebrospinal fluid (CSF) (oligoclonal banding)